CFD modeling and modal analysis for research of energy harvesters by wind loads

Abstract

This work aims at coupling computational fluid dynamics (CFD) and modal analysis (FEM) to simulate energy harvesting of wind loads to produce electrical energy by piezoelectric effect. To complement this objective, CFD-FEM simulation was performed by means of SolidWorks® 2021 add-ins, starting from the generation of the virtual model, computational domain definition, and imposition of wind loads, boundary conditions, and model discretization, by means of a mesh comprising a total of 84 709 nodes and 50 157 high order quadratic elements of 1 mm size and finally a mesh calibration was performed. The results showed that the section near the clamping base concentrated the highest pressures, regardless of the simulated velocity (3 to 21 m/s). The maximum velocity caused a pressure over the impact zone of 101 716 Pa, a relative pressure of 391.75 Pa, and shear stress of 4.78 Pa. The natural frequencies of vibration using the CFD output, range from 69 to 99 Hz. The direction of wind action is defined as the direction of piezoelectric placement, specifically near the base where the maximum effective voltage output (6.79 V) is obtained which, with an external resistance of 10 and 20 MΩ, produces an electrical power of 4.62 and 2.31 μW, respectively.